Flat panel displays (FPD) that can be manufactured in reduced size and thickness have been attracting attentions in recent years, and especially a liquid crystal display device, a typical type of the FPDs, has already been employed in a variety of equipments. At present, emissive devices (displays and light sources) using a self-emissive electroluminescence (hereinafter referred to as “EL”) element, particularly organic EL displays capable of emitting light at a high luminance in various colors depending on the organic compound material used, have been actively researched and developed.
In contrast to liquid crystal display devices in which the transmission rate of light from a back light is controlled by a liquid crystal panel disposed on a front surface thereof as a light valve, such organic EL display devices are self-emissive as described above, and therefore are bright and have excellent viewing angle characteristics in principle, achieving high-quality display.
Further, self-emissive elements, such as the above-described organic EL elements, can emit light with any wavelength of R (red), G (green), B (Blue), or the like with high color purity, and can be implemented in a very thin layer, so that such elements are highly advantageous in terms of reduction in thickness of the displays and the like.
The emitting element, however, includes a stacked layer structure composed of a multitude of functional thin layers, and different materials are used depending on the function of each layer, resulting in different refractive indices in different layers and tending to generate reflection at an interface between layers. As a result, light directly emitting from an emitting layer has a different phase from light reflected midway before emission, causing interference on the observation surface side, thereby easily generating variation in luminance and shift in white balance. Such interference increases color dependency of the viewing angle, i.e. color is varied from one observing direction to another, thereby lowering display quality as a display device.